Tiredness and Fatigue Blood Test, from our experts to you.
Dr Sam Rodgers MBBS, MRCGP

Chief Medical Officer meet our doctors

Expert Image

What can cause
tiredness and fatigue?

Most people experience fatigue and tiredness from time to time. It is one of the most common reasons why people visit their doctor. Tiredness is often a result of a recent virus or infection or sometimes simply from doing too much. However, for some people, a lack of energy becomes chronic and everyday tasks become more and more difficult.


What is a
Tiredness and Fatigue Blood Test?

Our Tiredness and Fatigue Blood Test investigates three causes of low energy and fatigue: iron deficiency anaemia, underactive thyroid, and low vitamin D, all of which can be improved through supplements or medication.


Who can take a
tiredness blood test?

Our test can help if you're feeling tired all of the time and want to find out whether there is a medical reason behind your symptoms. Alternatively, you can use this simple, home finger-prick test if you've taken steps to improve your iron and vitamin D and want to check your levels.


What's included?

Inflammation
Iron status
Thyroid hormones
Vitamins
Select profile for more information

CRP HS C-Reactive Protein (CRP) is an inflammation marker used to assess whether there is inflammation in the body - it does not identify where the inflammation is located. High Sensitivity CRP (CRP-hs) is a test used to detect low-level inflammation thought to damage blood vessels which can lead to a heart attack or stroke. When you suffer a serious injury or infection you experience significant inflammation around the site of injury - such as the swelling around a twisted ankle. Any injury like this will cause your CRP-hs to rise.
Iron Iron is a mineral that is essential for life. It is a component of haemoglobin, a protein in our red blood cells that is responsible for transporting oxygen around our body. If we don't have enough iron, our haemoglobin levels fall and we can't get sufficient oxygen to our cells. This can cause symptoms which include fatigue, dizziness, and shortness of breath. Serum iron is a very transient reading and can be influenced by the amount of iron-rich food in your diet in the days before your blood test. For this reason, iron is rarely looked at on its own, and is interpreted alongside other markers in an iron status test. 
TIBC Total iron-binding capacity (TIBC) is a measure of the ability of your body to efficiently carry iron through the blood.
Transferrin Saturation Transferrin is made in the liver and is the major protein in the blood which binds to iron and transports it round the body. This test measures how much this protein is 'saturated' by iron.
Ferritin Ferritin is a protein which stores iron in your cells and tissues. Usually, the body incorporates iron into haemoglobin to be transported around the body, but when it has a surplus, it stores the remaining iron in ferritin for later use. Measuring ferritin levels gives us a good indication of the amount of iron stored in your body.
TSH Thyroid stimulating hormone (TSH) is produced in the pituitary gland in order to regulate the production of thyroid hormones thyroxine (T4) and triiodothyronine (T3) by the thyroid gland. If thyroid hormones in the blood are low, then more TSH is produced to stimulate the thyroid gland to produce more of them. If thyroid hormone levels are high, then the pituitary produces less TSH to slow the production of thyroid hormones.  If TSH is too high or too low, it normally signifies that there is a problem with the thyroid gland which is causing it to under or over produce thyroid hormones. Sometimes a disorder of the pituitary gland can also cause abnormal TSH levels.
Free Thyroxine Thyroxine (T4) is one of two hormones produced by the thyroid gland. It works to speed up the rate of your metabolism. Most T4 is bound to carrier proteins in the blood - it is only the free, or unbound, T4 that is active in the body, which is measured in this test. Free T4 is the less active of the two main thyroid hormones. To have an impact on your cells it needs to convert to the more active T3 when your body needs it.
Vitamin D Although called a vitamin, vitamin D is actually a hormone which is activated by sunshine on your skin. Vitamin D is essential for bone strength as it helps your intestines absorb calcium. However, it is thought that vitamin D also plays an important role in immune function, as well as in many chronic diseases and mental health. Many people in the UK have low levels of vitamin D with symptoms including muscle weakness, mood swings and fatigue. People who have dark skin, as well as those who don't spend much time outdoors are particularly at risk of low vitamin D.  Small amounts of vitamin D can be obtained from food, especially oily fish, eggs and any food which has been fortified with vitamin D. If you are deficient in vitamin D you are unlikely to be able to improve your levels by food alone.

How to prepare
for your test

Special instructions

Prepare for your Tiredness and Fatigue Blood Test by following these instructions. Please take your sample before 10am. Take this test when any symptoms of short-term illness have settled. You should take this test before you take any medication or vitamin/mineral supplements. Do not take biotin supplements for two days before this test, discuss this with your doctor if it is prescribed.


Our latest customer reviews